= form_tag do
  = field_set do
    = field ProductMembership.human_attribute_name(:group), selector_tag(:group_id, {controller: :animal_groups, action: :unroll}, value: params[:group_id], new: backend_animal_group_path)
    = field ProductMembership.human_attribute_name(:started_at), datetime_field_tag(:started_at)
    = field Intervention.human_attribute_name(:production), selector_tag(:activity_production_id, {controller: :activity_productions, action: :unroll, scope: {of_current_campaigns: true} }, value: params[:activity_production_id])
  = form_actions do
    = submit_tag :add_to_group.ta
